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We present James Webb Space Telescope observations of the globular cluster NGC 6397 and use them to extend to infrared wavelengths the characterization of the cluster's entire white dwarf (WD) cooling sequence (CS). The data allows us to…

Solar and Stellar Astrophysics · Physics 2024-05-06 L. R. Bedin , D. Nardiello , M. Salaris , M. Libralato , P. Bergeron , A. J. Burgasser , D. Apai , M. Griggio , M. Scalco , J. Anderson , R. Gerasimov , A. Bellini

We analyze a ~70 ksec Chandra ACIS-I exposure of the globular cluster Omega Centauri (NGC 5139). The ~17 amin x 17 amin field of view fully encompasses three core radii and almost twice the half-mass radius. We detect 180 sources to a…

High Energy Astrophysical Phenomena · Physics 2011-02-11 Daryl Haggard , Adrienne M. Cool , Melvyn B. Davies

We present evidence that the globular cluster NGC 6397 contains two distinct classes of centrally-concentrated UV-bright stars. Color-magnitude diagrams constructed from U, B, V, and I data obtained with the HST/WFPC2 reveal seven UV-bright…

We present the results of a 47-ks Chandra-ACIS observation of the old open cluster M67. We detected 25 proper-motion cluster members (including ten new sources) and 12 sources (all new) that we suspect to be members from their locations…

Astrophysics · Physics 2009-11-10 Maureen van den Berg , Gianpiero Tagliaferri , Tomaso Belloni , Frank Verbunt

Our deep Chandra exposures of 47Tuc and moderate exposures of NGC 6397 reveal a wealth of new phenomena for interacting X-ray binaries (IXBs) in globular clusters. In this (late) Review, updated since the conference, I summarize recent and…

Astrophysics · Physics 2009-11-13 Jonathan E. Grindlay

We report our analysis of a Chandra X-ray observation of the rich globular cluster M80, in which we detect some 19 sources to a limiting 0.5-2.5 keV X-ray luminosity of 7*10^30 ergs/s within the half-mass radius. X-ray spectra indicate that…

We report a $30~\mathrm{ks}$ $Chandra$ ACIS-S survey of the globular cluster M3. Sixteen X-ray sources were detected within the half-light radius ($2.3'$) with $L_X \gtrsim 2.3 \times 10^{31}~\mathrm{erg~s^{-1}}$. We used…

High Energy Astrophysical Phenomena · Physics 2018-12-14 Yue Zhao , Craig O. Heinke , Haldan N. Cohn , Phyillis M. Lugger , Adrienne M. Cool

We report on the Chandra X-ray Observatory and Hubble Space Telescope observation of two low core density globular clusters, NGC6144 and E3. By comparing the number of X-ray sources inside the half-mass radius to those outside, we found 6…

High Energy Astrophysical Phenomena · Physics 2011-02-11 Shih Hao Lan , Albert K. H. Kong , Frank Verbunt , Walter H. G. Lewin , Cees Bassa , Scott F. Anderson , David Pooley

We present results of a study of the central regions of NGC 6397 using Hubble Space Telescope's Advanced Camera for Surveys, focusing on a group of 24 faint blue stars that form a sequence parallel to, but brighter than, the more populated…

Astrophysics of Galaxies · Physics 2011-02-11 R. R. Strickler , A. M. Cool , J. Anderson , H. N. Cohn , P. M. Lugger , A. M. Serenelli

We have used HST/FOS to study faint UV stars in the core of the nearby globular cluster NGC 6397. We confirm the presence of a 4th cataclysmic variable (CV) in NGC 6397 (CV 4), and we use the photometry of Cool et al. (1998) to present…

We present an observational far-UV (FUV) and near-UV (NUV) study of the core region of the globular cluster NGC 6397. The observations were obtained with the Space Telescope Imaging Spectrograph (STIS, FUV), and the Wide Field Camera 3…

Solar and Stellar Astrophysics · Physics 2017-05-31 Andrea Dieball , Armin Rasekh , Christian Knigge , Michael Shara , David Zurek

I review recent work on X-ray sources in Galactic globular clusters, identified with low-mass X-ray binaries (LMXBs), cataclysmic variables (CVs), millisecond pulsars (MSPs) and coronally active binaries by Chandra. Faint transient LMXBs…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Craig O. Heinke

We report the largest number of optical identifications of X-ray sources yet obtained in a single globular cluster. Using deep Chandra/ACIS-I imaging and extensive HST studies with WFPC2, we have detected optical counterparts to at least 22…

We present a deep ($\sim 330~\mathrm{ks}$) {\it Chandra} survey of the Galactic globular cluster M30 (NGC 7099). Combining the new Cycle 18 with the previous Cycle 3 observations we report a total of 10 new X-ray point sources within the…

We report the results of a deep search for faint Chandra X-ray sources, radio sources, and optical counterparts in the nearby, core-collapsed globular cluster, NGC 6752. We combined new and archival Chandra imaging to detect 51 X-ray…

We observed the globular cluster NGC 6652 with Chandra for 47.5 ks, detecting six known X-ray sources, as well as five previously undetected X-ray sources. Source A (XB 1832-330) is a well-known bright low-mass X-ray binary (LXMB). The…

High Energy Astrophysical Phenomena · Physics 2015-06-04 W. S. Stacey , C. O. Heinke , H. N. Cohn , P. M. Lugger , A. Bahramian

We combined Chandra ACIS observations of the globular cluster 47 Tucanae (hereafter, 47 Tuc) from 2000, 2002, and 2014-15 to create a deeper X-ray source list, and study some of the faint radio millisecond pulsars (MSPs) present in this…

High Energy Astrophysical Phenomena · Physics 2017-10-04 Souradeep Bhattacharya , Craig O. Heinke , Andrey I. Chugunov , Paulo C. C. Freire , Alessandro Ridolfi , Slavko Bogdanov

(Abridged) We present a Chandra observation of the supernova remnant (SNR) 3C 397 (G41.1-0.3) obtained with ACIS-S. Previous studies of this SNR have shown that it harbors a central X-ray `hot spot' suggestive of a compact object associated…

Astrophysics · Physics 2014-10-13 S. Safi-Harb , G. Dubner , R. Petre , S. S. Holt , P. Durouchoux

NGC 6397 is the second closest globular star cluster to the Sun. Using 5 days of time on the Hubble Space Telescope, we have constructed the deepest ever color-magnitude diagram for this cluster. We see a clear truncation in each of its two…

Cataclysmic variables (CVs) are tracers of dynamical evolution in globular clusters. A significant sample has been found by the relatively shallow \Halpha surveys conducted with HST thus far in just three globulars: NGC 6397 (3), NGC 6752…

Astrophysics · Physics 2007-05-23 Jonathan E. Grindlay